Because of the growing epidemic of obesity, insulin resistance, and Type 2 diabetes, we need more effective and sustainable prevention and treatment strategies for these serious disorders. Significant gaps exist in our knowledge of the molecular mechanisms underlying insulin resistance and Type 2 diabetes, which limit our ability to develop fully effective and safe therapies to treat these metabolic diseases. In this application, we strive to develop a new class of antidiabetic therapeutics based on a structurally novel class of bioactive lipids we recently discovered called Fatty Acid esters of Hydroxy Fatty Acids (FAHFAs). Characterization of one family of FAHFAs, Palmitic Acid esters of Hydroxy Stearic Acids (PAHSAs), revealed that these lipids possess a remarkable range of activities that improve glucose metabolism and reduce inflammation. PAHSAs stimulate insulin secretion and GLP1 secretion, improve systemic insulin sensitivity (i.e. they are insulin sensitizers), and reduce proinflammatory cytokine secretion in adipose tissue of obese mice. As natural compounds, PAHSAs were not designed for a particular target. Instead, these lipids utilize multiple pathways through at least two G protein coupled receptors (GPCRs). This powerful combination of beneficial activities and receptor targets uniquely positions PAHSAs as an exciting new class of compounds for the treatment of diabetes. In Aim 1, we will design, synthesize, and test PAHSAs and PAHSA analogs to enhance solubility, biological activity, and metabolic stability. This process will be iterative as we synthesize PAHSA analogs we will test them in biologic assays and metabolic stability studies in Aims 1 and 2 and use this information to design the next generation of analogs with improved properties. In Aim 2, we will investigate pharmacokinetics, efficacy, and toxicity of PAHSAs and PAHSA analogs to determine which compounds have the ideal stability, oral availability, safety, and activity. The information from these experiments will also assist in the design of new PAHSA analogs in Aim 1. Then in Aim 3, we will determine the roles of GPR40 and GPR120 in mediating PAHSA biological effects in vivo using knockout mice and biologic assays in tissues from these mice. A clear mechanism of action is required for drugs moving into the clinic, and the finding that PAHSAs target two intensely pursued anti-diabetic GPCR drug targets will amplify interest in developing PAHSA-based drugs. We will also perform broad target screening since PAHSAs might have additional receptors or pathways. The combination of the data obtained in Aim 3 will provide a comprehensive understanding of the contribution of GPR40, GPR120, and other PAHSA targets to PAHSA biology in vivo. This application will provide the structural, pharmacokinetic, toxicology, and mechanistic data needed to develop PAHSAs or PAHSA analogs into novel anti-diabetes therapeutics.